JP3965328B2 - Transmitting apparatus, receiving apparatus, and wireless communication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission device, a reception device, and a wireless communication method .
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a configuration in which a modulation unit of a wireless communication system using a digital orthogonal modulation scheme performs band limitation using a band limitation filter after digital modulation is widely used. FIG. 8 is a block diagram showing a configuration of a conventional signal processing apparatus. In FIG. 8, the signal processing apparatus 10 includes a digital modulator 11, a band limiting filter 12, and a quadrature modulator 13.
[0003]
The digital modulator 11 digitally modulates transmission data, generates an obtained quadrature modulation signal, and outputs it to the band limiting filter 12. The band limiting filter 12 limits the band of the quadrature modulation signal and outputs the obtained quadrature baseband signal to the quadrature modulator 13. The quadrature modulator 13 performs a quadrature modulation process on the band-limited quadrature baseband signal and outputs the obtained transmission modulation signal.
[0004]
[Problems to be solved by the invention]
However, in a conventional apparatus, a modulated signal with a limited band generates a peak power by overlapping signals (signal points) whose transmission times are adjacent. In particular, in the case of a signal modulated by the orthogonal multilevel modulation method, a signal having a large amplitude value is generated by overlapping signals having a large amplitude. As a result, there is a problem that the dynamic range of the modulated signal after band limitation is expanded. And the linearity which covers a dynamic range is requested | required of the apparatus which processes a modulation signal.
[0005]
The present invention has been made in view of this point, and an object thereof is to provide a transmission device, a reception device, and a wireless communication method capable of suppressing the dynamic range of a modulated signal after band limitation.
[0006]
[Means for Solving the Problems]
The transmission apparatus of the present invention detects that the digital modulation means for digitally modulating transmission data and the transition of the signal point of the modulation signal obtained by the digital modulation means is a predetermined transition that generates peak power. If so, a phase control means for changing the phase of the signal point of the modulation signal, and a control signal indicating how much the phase of the signal point of the modulation signal has been changed by the phase control means are generated and transmitted. And a control signal generating means .
[0007]
The receiving apparatus of the present invention comprises: phase control means for controlling the phase of the received modulated signal based on phase change information indicating the phase change amount of the signal point of the received modulated signal modulated by the digital modulation method; and the phase Demodulating means for demodulating the received modulated signal after control, and the phase change information is information transmitted from a transmitting apparatus that transmits the modulated signal, and the signal point of the digital modulated signal in the transmitting apparatus The configuration is information indicating the phase change amount of the signal point before the transition and the signal point after the transition at the signal point before the band limitation where it is determined that the generation of the peak power is accompanied by the generation of the peak power .
[0013]
In the wireless communication method of the present invention, when it is determined on the transmission side that peak power is generated from the transition of the signal point of the signal modulated by the digital modulation method, the signal point before the modulation signal transition or after the transition before the band limitation The phase of the signal point is changed, and the phase of the modulated signal after the phase change is controlled on the receiving side to obtain the modulated signal before the phase change.
[0014]
According to this method, by changing the phase of the signal after quadrature demodulation in accordance with the phase change information, it is determined that peak power is generated on the transmission side, and either the signal before or after the transition of the modulation signal A signal transmitted by changing the phase of a point can be correctly demodulated after reception.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present inventor has found that when the band of a digitally modulated signal is limited, adjacent signals are overlapped to generate intersymbol interference, and signals having large amplitude are overlapped with each other to generate a signal having high peak power. I came to do.
[0016]
That is, the gist of the present invention is to determine the generation of peak power from the transition of the signal point of the signal modulated by the digital modulation method, and when it is determined that the peak power is generated, the signal point before the transition of the modulation signal and the post-transition Is to prevent the signals having large amplitudes from overlapping each other and to prevent generation of a signal having large peak power. Then, the increase in the dynamic range required for the communication device that transmits the modulated signal after the band limitation is alleviated.
[0017]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the signal processing apparatus according to Embodiment 1 of the present invention. 1 mainly includes a digital modulator 101, a modulation signal determination unit 102, a control signal generator 103, a phase controller 104, a band limiting filter 105, and a quadrature modulator 106. Composed.
[0018]
In FIG. 1, a digital modulator 101 digitally modulates transmission data and outputs the obtained modulated signal to a modulation signal determination unit 102 and a phase controller 104. For example, the digital modulator 101 maps transmission data according to a signal point arrangement determined by quadrature amplitude modulation such as 16QAM (Quadrature Amplitude Modulation) method, and obtains a modulated signal.
[0019]
The modulation signal determination unit 102 determines whether or not peak power is generated from the transition of the signal point of the modulation signal for the modulation signal modulated by the digital modulator 101. For example, the modulation signal determination unit 102 measures the transition of signal points that are continuous for a predetermined two unit times, the signal point before transition and the signal point after transition have the same phase, and both signal points have the maximum amplitude value. If it is, it is determined that peak power is generated.
[0020]
Then, the modulation signal determination unit 102 outputs the determination result to the control signal generator 103. For example, when it is determined that peak power is generated, the modulation signal determination unit 102 outputs a determination result “1”. When it is determined that peak power is not generated, the modulation signal determination unit 102 outputs a determination result “0”. Output.
[0021]
When the determination result of the modulation signal determination unit 102 is a determination that peak power is generated, the control signal generator 103 outputs the phase control signal that has been phase-shifted to the phase controller 104 and the outside. Further, the control signal generator 103 outputs a phase control signal that is not phase-shifted to the phase controller 104 when the determination result of the modulation signal determination unit 102 is a determination that peak power is not generated. This phase control signal has a unit vector, that is, an amplitude value of “1” (no unit), changes only the phase of the modulation signal, and does not change the amplitude value.
[0022]
The phase controller 104 changes the phase of the modulation signal using the control signal output from the control signal generator 103. For example, the phase controller 104 performs complex multiplication on the control signal output from the control signal generator 103 and the modulation signal, and outputs the obtained modulation signal to the band limiting filter 105. Of the signal points of the modulation signal, the signal point for changing the phase may be either a signal point before transition or a signal point after transition.
[0023]
For example, the phase controller 104 changes the phase of the signal point after the transition by 90 degrees to change the phase difference between the signal point before the transition and the signal point after the transition.
[0024]
As a result, when it is determined that peak power is generated, the phase difference between the signal point before the transition of the modulation signal and the signal point after the transition changes. Further, when it is determined that no peak power is generated, the phase difference between the signal point before the transition of the modulation signal and the signal point after the transition does not change.
[0025]
The band limiting filter 105 limits the band of the modulation signal output from the phase controller 104. Then, the band limiting filter 105 outputs the band-limited modulated signal to the quadrature modulator 106 as a quadrature baseband signal. The quadrature modulator 106 modulates and outputs a quadrature baseband signal.
[0026]
Next, the operation of the signal processing apparatus according to this embodiment will be described. FIG. 2 is a flowchart showing an example of the operation of the signal processing apparatus according to the present embodiment.
[0027]
In step (hereinafter referred to as “ST”) 201, transmission data is digitally modulated in digital modulator 101. In ST202, modulated signal determining section 102 determines whether or not peak power is generated in the modulated signal. When peak power is generated in the modulation signal, the process proceeds to ST203, and when peak power is not generated in the modulation signal, the process proceeds to ST204.
[0028]
In ST203, the phase of the modulated signal is changed by a predetermined amount in the phase controller 104. In ST204, the band limiting filter 105 limits the band of the modulation signal. In ST205, the quadrature modulator 106 subjects the modulated signal to quadrature modulation.
[0029]
Thus, according to the signal processing device of the present embodiment, the occurrence of peak power is determined from the signal point transition of the signal modulated by the digital modulation method, and when the signal point transition is a predetermined transition, It is determined that peak power is generated, and the phase of either one of the signal points before or after the transition of the modulation signal is changed to prevent signals with large amplitudes from overlapping with each other and to prevent generation of signals with large peak power. It is possible to suppress the dynamic range of the modulated signal after band limitation.
[0030]
In the above description, when the signal point before transition and the signal point after transition have the same phase and both signal points have the maximum amplitude value, it is determined that peak power is generated. There are no particular limitations as long as the conditions occur.
[0031]
Hereinafter, an example of determining that peak power is generated will be described. FIG. 3 is a diagram illustrating an example of a 16QAM signal point arrangement. In FIG. 3, signal points 301 to 334 indicate signal points modulated by 16QAM.
[0032]
For example, when the signal points 301 are continuous, the modulation signal determination unit 102 determines that peak power is generated because the signal points before and after the transition have the same phase and both signal points have the maximum amplitude value. Similarly, when the signal point 311 is continuous, the signal point 321 is continuous, or the signal point 331 is continuous, the modulation signal determination unit 102 has the same phase before and after the transition, and both signals Since the point is the maximum amplitude value, it is determined that peak power is generated.
[0033]
As another example, when the modulation signal determination unit 102 makes a transition from the signal point 301 to the signal point 301 or the signal point 321, the signal points before and after the transition have the same phase or a phase different by 180 degrees, and both It is determined that the signal point has the maximum amplitude value and peak power is generated. Similarly, the modulation signal determination unit 102 changes the signal point 311 to the signal point 311 or the signal point 331, or changes from the signal point 321 to the signal point 321 or the signal point 301. When transitioning to the signal point 311, it is determined that the signal points before and after the transition have the same phase or a phase different by 180 degrees, both signal points have the maximum amplitude value, and peak power is generated.
[0034]
As another example, when the modulation signal determination unit 102 makes a transition from one of the signal points 301, 302, and 303 to one of the signal points 301, 302, and 303, each of the signal points before and after the transition has a maximum amplitude. If the signal points or distance between signal points in the signal point before Symbol maximum amplitude, of either of the nearest signal point, it is determined that the peak power is generated.
[0035]
Similarly, when the modulation signal determination unit 102 transitions from any of the signal points 311, 312, 313 to any of the signal points 311, 312, 313, the modulation signal determination unit 102 determines that the modulation signal determination unit 102 has the signal points 321, 322, 323. When any of the signal points 321, 322, and 323 is changed, the modulation signal determination unit 102 changes from any of the signal points 331, 332, and 333 to any of the signal points 331, 332, and 333. case, each signal point before and after the transition is either the maximum amplitude signal points, or pre-Symbol maximum amplitude signal point distance is nearest signal point to the signal points of, it is determined that the peak power is generated.
[0036]
As another example, the modulation signal determination unit 102 changes when the signal point 301 changes to one of the signal points 301, 302, and 303, or when the signal point 301, 302, and 303 changes to the signal point 301. is any signal point, or the signal point distance is closest signal point in the signal point before Symbol maximum amplitude of the maximum amplitude each signal point before and after the transition, and one of the signal points before and after the transition of the maximum amplitude Since it is a signal point, it is determined that peak power is generated.
[0037]
Similarly, the modulation signal determination unit 102 determines whether the signal point 311 transitions from the signal point 311, 312, 313, the signal point 311, 312, 313 to the signal point 311, or the signal point 321 A transition to any of the points 321, 322, 323, a transition from the signal point 321, 322, 323 to the signal point 321, a transition from the signal point 331 to any of the signal points 331, 332, 333, or when making a transition from the signal point 331, 332, 333 to the signal point 331, any respective signal points before and after the transition is the maximum amplitude signal points, or pre-Symbol maximum amplitude signal point distance is nearest signal point to the signal points of Since one of the signal points before and after the transition is a signal point with the maximum amplitude, it is determined that peak power is generated.
[0038]
As another example, the modulation signal determination unit 102 transitions from one of signal points 301, 302, 303, 321, 322, and 323 to one of signal points 301, 302, 303, 321, 322, and 323. If the signal point of each signal point is the maximum amplitude of the longitudinal transition or prior Symbol maximum amplitude signal point and the maximum amplitude signal point of 180 ° different phases of, and the inter any signal point and the signal point distance is most It is one of the close signal points, and it is determined that peak power is generated.
[0039]
Similarly, the modulation signal determination unit 102 transitions when any of the signal points 311, 312, 313, 331, 332, 333 transitions to any of the signal points 311, 312, 313, 331, 332, 333. signal points of maximum amplitude, respectively before and after the signal point, or before Symbol maximum amplitude signal point and the maximum amplitude signal point of 180 ° different phases of and the one of signal points and distance between signal points nearest signal point It is either, and it is determined that peak power is generated.
[0040]
As another example, the modulation signal determination unit 102 changes from the signal point 301 or 321 to any of the signal points 301, 302, 303, 321, 322, and 323, or the signal points 301, 302, and 303. the maximum in the case of transition from any of 321, 322, 323 signal points 301 or 321, the signal points of each signal point is the maximum amplitude of the longitudinal transition, or the pre-Symbol maximum amplitude signal point and 180 ° phase different Peak power is generated because the amplitude signal point is one of the signal points with the shortest distance between any of the signal points and one of the signal points before and after the transition is the maximum amplitude signal point. Judge that.
[0041]
Similarly, the modulation signal determination unit 102 transitions from the signal point 311 or 331 to any of the signal points 311, 312, 313, 331, 332, 333, or the signal points 311, 312, 313, 331, 332. , in case of transition from one of 333 to the signal point 311 or 331, the signal point of the maximum amplitude signal point and the 180-degree different phases of the signal points or pre Symbol maximum amplitude, the maximum amplitude each signal point before and after the transition Since any one of the signal points and the signal point having the shortest distance between the signal points is one of the signal points before and after the transition, the signal point having the maximum amplitude is determined.
[0042]
In addition, the digital modulation method of the signal handled by the signal processing apparatus according to the present embodiment is not particularly limited, and a modulation method that may generate peak power, for example, a quadrature amplitude modulation method such as 16QAM or 64QAM is applied. Can do.
[0043]
When a signal point having a large amplitude in the digital quadrature amplitude modulation system is continuous, the generation of a signal having a large peak power can be prevented and the dynamic range of the modulated signal after band limitation can be suppressed.
[0044]
In the above description, when it is determined that peak power is generated, the modulation signal determination unit 102 outputs a determination result “1”. When it is determined that peak power is not generated, the modulation signal determination unit 102 Although an example in which “0” is output has been described, it is only necessary to be able to distinguish the determination results, and any value can be applied as long as the signal can identify two states.
[0045]
In the above description, the amplitude value of the phase control signal is set to “1” and only the phase is changed without changing the amplitude value of the modulation signal. The amplitude value may be greater than or equal to “1” or less than “1”, the phase of the modulation signal may be changed, and the amplitude value of the modulation signal may be amplified or attenuated.
[0046]
In the above description, the phase of the modulation signal is changed by 90 degrees, but the amount of phase change is not limited to this. For example, the phase of the modulation signal may be changed by 135 degrees. In the case of multi-level quadrature amplitude modulation such as 16QAM, the signal point after changing the phase does not overlap with other signal points by changing the phase to 135 degrees or the like. It is also possible to distinguish and transmit signal points that have not been transmitted.
[0047]
Further, the amount of change in phase does not have to be constant, and any change amount can be used as long as the peak power can be reduced.
[0048]
Further, in the above embodiment, when it is determined that no peak power is generated, the phase difference between the signal point before the transition of the modulation signal and the signal point after the transition does not change. Not limited to. For example, when it is determined that no peak power is generated, the phase of the signal point before or after the transition of the modulation signal may be set as a predetermined phase.
[0049]
Next, the receiving side will be described. FIG. 4 is a block diagram showing a configuration of the signal processing apparatus according to Embodiment 1 of the present invention. 4 mainly includes a quadrature demodulator 401, a control signal extractor 402, a phase controller 403, and a digital demodulator 404.
[0050]
The quadrature demodulator 401 demodulates the received quadrature modulation signal and outputs a quadrature baseband signal to the phase controller 403. The control signal extractor 402 extracts phase change information from the received signal and outputs it to the phase controller 403.
[0051]
The phase controller 403 changes the phase of the quadrature baseband signal in accordance with the phase change information and outputs the changed signal to the digital demodulator 404. The digital demodulator 404 demodulates the quadrature baseband signal according to a signal point arrangement determined by quadrature amplitude modulation such as 16QAM, and obtains received data.
[0052]
Next, the operation of the signal processing apparatus according to this embodiment will be described. FIG. 5 is a flowchart showing an example of the operation of the signal processing apparatus according to the present embodiment.
[0053]
In ST501, the orthogonal demodulator 401 orthogonally demodulates the received orthogonal modulation signal. In ST502, control signal extractor 402 determines whether or not phase change information is included in the control signal in the received signal. If the control signal includes phase change information, the phase change information is output to phase controller 403, and the process proceeds to ST503. If the phase change information is not included in the control signal, the process proceeds to ST504.
[0054]
In ST503, phase controller 403 changes the phase of the orthogonal baseband signal. In ST504, digital demodulator 404 digitally demodulates the orthogonal baseband signal to obtain received data.
[0055]
As described above, according to the signal processing apparatus of the present embodiment, it is determined that peak power is generated on the transmission side by changing the phase of the signal after quadrature demodulation according to the information on the phase change, and the modulation signal A signal transmitted by changing the phase of one of the signal points before or after transition can be correctly demodulated after reception.
[0056]
(Embodiment 2)
FIG. 6 is a block diagram showing a configuration of a communication apparatus according to Embodiment 2 of the present invention. 6 mainly includes signal processing apparatus 100 according to the first embodiment, radio transmission section 601 and phase information transmission section 602.
[0057]
The signal processing apparatus 100 digitally modulates transmission data, determines the generation of peak power from the transition of signal points of a signal modulated by the digital modulation method, and determines that peak power is generated, The phase difference between the signal point and the signal point after the transition is changed. Then, the signal processing apparatus 100 transmits the modulation signal to the wireless transmission unit 601 and outputs information on the phase change of the modulation signal to the phase information transmission unit 602.
[0058]
The wireless transmission unit 601 converts the modulated signal output from the signal processing apparatus 100 into a radio frequency and transmits the radio signal. The phase information transmission unit 602 encodes, modulates, converts the information on the phase change of the modulated signal output from the signal processing apparatus 100 into a radio frequency, and transmits the information.
[0059]
As described above, according to the communication apparatus of the present embodiment, the occurrence of peak power is determined from the signal point transition of the signal modulated by the digital modulation method, and when the signal point transition is a predetermined transition, By determining that power is generated and changing the phase of one of the signal points before or after the transition of the modulation signal, it is possible to prevent signals with large amplitudes from overlapping each other and to prevent generation of signals with large peak power. The dynamic range of the modulated signal after limitation can be suppressed. As a result, the communication apparatus can suppress the dynamic range of the transmission signal.
[0060]
Further, according to the communication apparatus of the present embodiment, it is possible to omit the phase change determination operation on the receiving side by transmitting information on the amount of change in the phase difference of the modulated signal in the signal processing apparatus.
[0061]
Next, the operation on the receiving side will be described. A communication apparatus 700 in FIG. 7 mainly includes a signal processing apparatus 400 according to the first embodiment, a wireless reception unit 701, and a phase information reception unit 702.
[0062]
The wireless reception unit 701 receives a signal transmitted from the communication device 600, converts the frequency to a baseband signal, and outputs the baseband signal to the signal processing device 400. The phase information receiving unit 702 receives information on the phase change of the modulated signal transmitted from the communication device 600, converts it to a baseband frequency, demodulates and decodes it, and outputs it to the signal processing device 400. The signal processing apparatus 400 performs phase control on the baseband signal output from the wireless reception unit 701 in accordance with phase change information, and then demodulates the baseband signal to obtain received data.
[0063]
As described above, according to the communication apparatus of the present embodiment, it is determined that peak power is generated on the transmission side by changing the phase of the signal after quadrature demodulation according to the phase change information, and the transition of the modulation signal A signal transmitted by changing the phase of one of the signal points before or after transition can be correctly demodulated after reception.
[0064]
In addition, this invention is not limited to the said embodiment, It can change and implement variously. For example, although cases have been described with the above embodiments as a signal processing device and a communication device, the present invention is not limited to this, and this signal processing method can also be performed as software.
[0065]
For example, a program for executing the signal processing method may be stored in advance in a ROM (Read Only Memory), and the program may be operated by a CPU (Central Processor Unit).
[0066]
A program for executing the above signal processing method is stored in a computer-readable storage medium, the program stored in the storage medium is recorded in a RAM (Random Access memory) of the computer, and the computer operates according to the program. You may make it let it.
[0067]
【The invention's effect】
As described above , according to the present invention, the occurrence of peak power is determined from the signal point transition of the signal modulated by the digital modulation method, and the peak power is generated when the signal point transition is a predetermined transition. Then, the phase of either one of the signal points before and after the transition of the modulation signal is changed and the signals with large amplitude are prevented from overlapping with each other, and the signal with large peak power is prevented from being generated. The dynamic range of the modulation signal can be suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a signal processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a flowchart showing an example of operation of the signal processing apparatus according to the embodiment. FIG. 4 is a block diagram showing the configuration of the signal processing apparatus according to the above embodiment. FIG. 5 is a flowchart showing an example of the operation of the signal processing apparatus according to the above embodiment. FIG. 7 is a block diagram showing a configuration of a communication apparatus according to a second embodiment of the present invention. FIG. 7 is a block diagram showing a configuration of a communication apparatus according to the embodiment. FIG. 8 is a block diagram showing a configuration of a conventional signal processing apparatus. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Digital modulator 102 Modulation signal determination part 103 Control signal generator 104,403 Phase controller 105 Band-limiting filter 106 Orthogonal modulator 401 Orthogonal demodulator 402 Control signal extractor 404 Digital demodulator 601 Wireless transmission part 602 Phase information transmission part 701 Radio reception unit 702 Phase information reception unit

Claims (6)

Digital modulation means for digitally modulating transmission data;
Phase control for changing the phase of the signal point of the modulation signal when it is detected that the signal point transition of the modulation signal obtained by the digital modulation means is a predetermined transition that generates peak power Means,
Control signal generation means for generating and transmitting a control signal indicating how much the phase of the signal point of the modulation signal has been changed by the phase control means;
A transmission apparatus comprising: The phase control means is provided between the digital modulation means and a band limiting filter.
The transmission device according to claim 1. The signal point transition is a signal point transition of a temporally continuous modulation signal before band limitation.
The transmission apparatus according to claim 1 or 2. It said phase control means, transmitting apparatus according to any one of claims 3 to unit vector from claim 1 for multiplying the modulated signal. Phase control means for controlling the phase of the received modulation signal based on phase change information indicating the phase change amount of the signal point of the received modulation signal modulated by the digital modulation method;
Demodulation means for demodulating the received modulated signal after the phase control;
Comprising
The information on the phase change is
Information transmitted from a transmission apparatus that transmits the modulated signal, and the transition of the signal point of the digital modulation signal at the transmission apparatus is determined to be accompanied by generation of peak power. Information indicating the amount of phase change at the signal point and the signal point after transition
Receiver device. If the transmitter determines that peak power is generated from the transition of the signal point of the signal modulated by the digital modulation method, the phase of the signal point before or after the transition of the modulated signal is changed before band limitation. The receiving side controls the phase of the modulated signal after the phase change to obtain the modulated signal before the phase change.
Wireless communication method .

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